1. Field of the Invention
This invention relates generally to electical equipment, and more specifically to means for housing electric devices such as switches and outlets.
2. Brief Description of the Prior Art
Electical boxes formed from sheet metal or plastic materials are widely used for housing electrical devices such as switches, outlets, and the like, and for permanently mounting such devices in walls, ceilings or floors. Typically such boxes are anchored by nailing or otherwise permanently affixing the box, or a bracket on which such a box can be mounted, to a structural element such as a wall stud, a ceiling or floor joist, or the like. Once the box has been mounted in this manner, it is very difficult to remove or reposition. The box is usually mounted so that its outward, open face is flush with the surface, such as a wall, in which it is mounted. After mounting the box, wiring is brought into it for connection to the electrical device which it is intended to house. The function of the box is to provide a means of mounting the electrical device, and to isolate the electrical device from its environment to reduce potential electrical shock and fire hazards.
As new housing becomes increasingly expensive, the rehabilitation and remodeling of existing housing becomes increasingly attractive. Often older housing which is to be reconditioned has walls and ceilings which have numerous esthetic and/or structural deficiencies. It is frequently desirable to install new sheet stock, such as sheetrock, foam insulation, or laminated "paneling," directly over the existing surfaces, rather than remove the existing walls and ceilings first. When this is done, holes can be cut for existing switch and outlet boxes. However, when the new sheet stock has been installed, the existing boxes are no longer flush with the surface, but rather are set back in the surface by the thickness of the new sheet stock. Also, in new work boxes are often set crooked, and some even stick out too far. For esthetic and practical reasons, the electrical devices, including switches and outlets, must be positioned at the surface. However, the existing boxes can no longer adequately serve their protective function, since the portion of the electric device extending between the surface and the box will be exposed to the surrounding sheet material. Actually moving the box so that its face is flush with the new surface is not practical, since this would likely entail disconnecting the device from its associated wiring and extensive additional labor.
The prior art has approached this problem by fashioning box extentions of two different general types. The first type has walls of the same general configuration as the box to be extended, and of a fixed depth or thickness. The extension is simply screwed onto the existing box, and the electrical device is screwed onto the extention. Although this type of extension is available is a variety of thicknesses or depths, the fact that the thickness is fixed is often a disadvantage, since several layers of new sheet stock may be installed, and the resulting surface will frequently lie at some non-standard height above the original surface.
The second type of extension has a body which slidably extends within the existing box and relies on a friction fit with the interior surface of the existing box for mounting. This type of extension may not provide a secure mounting for the installed electrical device. For example, an outlet may be pushed back into the wall in which it is mounted when an electrical plug is forcefully inserted. Worse still, when a plug is repeatedly removed and reinserted, the outlet may be may be alternately pulled and pushed, stressing and loosening the wires supplying power to the outlet.
There is a need for an electrical box extension which can be used to safely and securely mount an electrical device such as a switch or outlet flush with a new surface on an electrical box fixed in an underlying existing surface, and in new construction there is a need for a new, integerally adjustable electric box to correct the alignment of the box which is set crooked, out too far, or too deep.